Science notes: Stem cells might help transplant patients

March 10, 2012 - 6:06 PM

A new study suggests that patients receiving an organ that's less than a perfect match can be protected against rejection by a second transplant -- this time of the organ donor's imperfectly matched stem cells.

Though preliminary, the new study is being hailed as a potential game-changer in the field of transplantation, a mystifying development that could offer hope to hundreds of thousands of patients who await or have received donor kidneys and depend on a harsh regimen of daily anti-rejection pills.

The pilot study, reported in the journal Science Translational Medicine, describes a novel regimen that combined old-fashioned cancer treatments with 21st-century cell therapy to induce five patients' immune systems to accept donor kidneys as their own despite significant incompatibility.

If the technique proves successful in a larger group of people, future transplant patients may need to take anti-rejection drugs only briefly. The recipients of other organs, including heart, lung, liver and pancreas, might also benefit. It could offer hope, too, for patients receiving bone marrow transplants to treat blood cancers, speeding the process of finding a donor.

"Few transplant developments in the past half century have been more enticing," wrote pioneer transplant surgeons James F. Markmann and Tatsuo Kawai of Massachusetts General Hospital, in a commentary accompanying the study. If borne out, they wrote, the findings "may potentially have an enormous, paradigm-shifting impact on solid-organ transplantation."

In this case, five of the study's eight participants -- age 35 to 46 -- were able to discontinue their use of immunosuppressants after a year. The team was led by transplant specialist Dr. Suzanne Ildstad, director of the Institute for Cellular Therapeutics at the University of Louisville in Kentucky. In a controversial move to protect their commercial interest in the newly described therapy, the authors declined to detail how they refined each donor's stew of cells into an elixir enriched for adult stem cells and a heretofore unrecognized class of cells dubbed "tolerogenic graft-facilitating cells."

REPORT: TEEN SMOKING STUNTS LUNG GROWTH

Smoking during the teenage years stunts lung growth and accelerates the decline in their function that inevitably comes with age. At the same time, the habit damages blood vessels in ways that can later lead to heart attack, stroke and aortic rupture. Those are among the conclusions of a 899-page report by the U.S. surgeon general.

Lung function usually doesn't begin to decline until after age 45 in men. But in those who started smoking as teenagers and kept at it, that change began almost 15 years earlier.

And early smoking also affects the cardiovascular system. Researchers reviewed autopsy results for white men ages 25 to 34 killed by trauma or homicide and found that smokers were twice as likely to have advanced damage of the abdominal aorta as nonsmokers. "This ... profile of risk suggests that the effect of tobacco smoking begins at a young age and is cumulative," the authors wrote.